Coating composition

ABSTRACT

The coating agent composition comprises an emulsion containing (A) polydiorganosiloxane having a viscosity of 50 to 10,000,000 mPa·s at 25° C. and having both terminal ends blocked by hydroxyl groups, (B) polyorganohydrogensiloxane having at least three hydrogen atoms bonded to silicon atoms in one molecule, (C) a curing catalyst, and (D) chlorinated polyolefine and/or acryl-modified polyolefine, with which (E) fine spherical particles comprised of a rubber-like elastomer having hardness of less than 90 are mixed to disperse into it. The coating agent composition having good uniform applying property, non tackness, water repellency and lubricating properties and outstanding adhesiveness to a rubber or plastic substrate can be obtained.

TECHNICAL FIELD

The present invention relates to a coating agent composition, and moreparticularly to a coating agent composition which can be coated on thesurface of a substrate of rubber, plastic or the like to form a coatingfilm having non tackness, water repellency and lubricating propertiesand also excelling in adhesiveness and abrasion resistance.

BACKGROUND ART

Conventionally, ethylene-propylene-diene ternary copolymer (EPDM) rubberand various types of rubber products used as automobile weather-stripsare coated with a coating agent comprised of a polyorganosiloxanecomposition to provide their surfaces with non tackness, waterrepellency, abrasion resistance and lubricating properties.

Such a coating agent is known to be, for example, a composition whichcontains polydiorganosiloxane having hydroxyl groups at the terminalends and polyorganosiloxane having hydrogen atoms bonded to siliconatoms and/or organoalkoxysilane and a curing catalyst.

But, such a coating agent composition generally contains an organicsolvent and has safety and hygienic problems, handling problemsresulting from flammability, and a problem of a large averse effect onnatural environments. Therefore, a water-based emulsion type coatingagent not containing an organic solvent is under development in theseyears.

But, if a coating agent of a type diluted with an organic solvent isdirectly applied to a water-based type, a coating film cannot beprovided with satisfactory durability and adhesiveness (adhesion). And,there is also a problem that it is hard to provide a water-based typebecause a silane component reacts with water.

Meanwhile, as an emulsion type silicone (polyorganosiloxane) basedcoating agent, a composition containing various types of siloxanecompounds is proposed (e.g., Patent Document 1).

But, this coating agent does not provide satisfactory adhesiveness andabrasion resistance of the coating film, and particularly does notprovide a non foamed rubber material or a substantially non foamedrubber material with the coating film having satisfactory adhesivenessand film strength. There are also problems that the storage stability ofthe emulsion and the usable life after blending individual componentsare not satisfactory.

To improve the adhesiveness and abrasion resistance of the coating film,there is proposed a coating agent including a dealcoholic condensationtype silicone-based emulsion mixed with chlorinated polyolefine having amaleic anhydride group (e.g., Patent Document 2).

In the coating agent described in Patent Document 2, however, the maincomponent silicone is a dealcoholic condensation type silicone, and theadhesiveness and abrasion resistance of the coating film are notsatisfactory.

Besides, there is also proposed a coating agent, which is adehydrogenation condensation type silicone emulsion mixed with aparticular adhesion improving component (such as an amino silanecompound, an epoxy silane compound or carboxylic acid) (e.g., PatentDocument 3).

But, the above coating agent is not satisfactory in terms of a uniformapplying property, non tackness, water repellency, lubricatingproperties and adhesiveness with the substrate and demanded for furtherimprovement.

Besides, a dealcoholic condensation type coating agent, which containsorganotrialkoxysilane as a crosslinking component, and an amide group, acarboxyl group-containing organotrialkoxysilane and epoxy groupcontaining trialkoxysilane as adhesiveness improving components, isproposed in these years (e.g., Patent Document 4).

But, this coating agent is also not satisfactory in the adhesiveness andabrasion resistance of the coating film, and a mixing method and ausable life after mixing have problems because silane having ahydrolysis property in the presence of a catalyst is mixed.

Furthermore, the coating agent is demanded in these years that, when acoated mold part in a wet state is rubbed against glass or the like,frictional sound, so-called creaking sound, is not produced or thecoated surface is not damaged because of rubbing with the coated metalsurface.

Patent Document 1: JP-A HEI 8-245882

Patent Document 2: JP-A 2001-207106

Patent Document 3: JP-A 2002-188057

Patent Document 4: JP-A 2003-155411

SUMMARY OF THE INVENTION

The present invention provides a coating agent, which has good storagestability, uniform applying property, non tackness, water repellency,usable life and lubricating properties, and particularly improvedadhesiveness and abrasion resistance to a substrate, as a treating agentfor the surface of the substrate, for example, as a water-based coatingagent for a sheet of EPDM or the like and a molded product.

The invention also provides a water-based coating agent which isimproved in its adverse effect on a coated metal surface beingemphasized in these years and does not produce creaking sound even ifrubbed against glass in a water-wet state.

The present inventors have made a devoted study in order to achieve theabove-described objects and completed the present invention by findingthat a water-based coating agent having outstanding properties can beobtained by mixing fine spherical particles having rubber-likeelasticity with an emulsion containing a particular silicone polymer andchlorinated polyolefine and/or acryl-modified polyolefine.

The coating agent composition of the present invention includes anemulsion containing (A) polydiorganosiloxane having a viscosity of 50 to10,000,000 mPa·s at 25° C. and having both terminal ends blocked byhydroxyl groups, (B) polyorganohydrogensiloxane having at least threehydrogen atoms bonded to silicon atoms in one molecule, (C) a curingcatalyst and (D) chlorinated polyolefine and/or acryl-modifiedpolyolefine, with which (E) fine spherical particles comprised of arubber-like elastomer having hardness of less than 90 are mixed todisperse into it.

In the coating agent composition, the component (E) can be finespherical particles comprised of a rubber-like elastic material havinghardness of 60 to 80. A total content of the chlorinated polyolefine andthe acryl-modified polyolefine of the component (D) can be 5 to 150parts by weight to 100 parts by weight of the polydiorganosiloxane ofthe component (A). And, the content of the fine spherical particles ofthe rubber-like elastic material of the component (E) can be 10 to 150parts by weight to 100 parts by weight of the polydiorganosiloxane ofthe component (A). And, alkylamine oxide and/or water-insoluble aminogroup-containing polyorganosiloxane can also be contained.

Besides, this coating agent composition can be coated on a mold partwhich is formed of an foamed or non foamed EPDM.

According to the coating agent composition of the present invention, acoating film having quite outstanding adhesiveness and good lubricatingproperties, non tackness and water repellency can be formed on thesubstrate formed of rubber or plastic, and particularly on the substrateformed of foamed or non foamed EPDM rubber. This coating film also has alow coefficient of friction and outstanding abrasion resistance.

Therefore, the coating agent composition of the present invention can beused suitably as a surface treatment agent for rubber parts such asautomobile weather-strips, printer blades, rubber vibration-isolators,construction material gaskets for which EPDM rubber and various types ofrubbers are used.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a perspective view showing a rubbing part used for an abrasionresistance test in the embodiments of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

The preferred embodiments of the present invention will be described. Itis to be understood that the present invention is not limited to theembodiments described below.

The embodiment of the coating agent composition according to the presentinvention includes an emulsion containing (A) polydiorganosiloxanehaving a viscosity of 50 to 10,000,000 mPa·s (at 25° C.) and having bothterminal ends blocked by hydroxyl groups, (B) polyorganohydrogensiloxanehaving at least three hydrogen atoms bonded to silicon atoms in onemolecule, (C) a curing catalyst and (D) chlorinated polyolefine and/oracryl-modified polyolefine. And, (E) fine spherical particles comprisesof a rubber-like elastomer having hardness of less than 90 are mixed todisperse into the emulsion.

This embodiment will be described in detail below.

The polydiorganosiloxane having the terminal ends blocked by thehydroxyl group of the component (A) has the hydroxyl group bonded tosilicon atom at the terminal ends of the molecule and is concerned in acuring reaction by its reactivity.

Specific examples of an organic group bonded to the silicon atoms in thepolydiorganosiloxane are an alkyl group such as a methyl group, an ethylgroup, a propyl group, a butyl group or a hexyl group; an alkenyl groupsuch as a vinyl group or a propenyl group; an aryl group such as aphenyl group; an aralkyl group such as a phenethyl group; and one whichhas a part of hydrogen atoms of their hydrocarbon groups replaced with ahalogen atom, a nitril group and so on. And, the methyl group isdesirable taking the ease of synthesis and the physical properties ofthe cured coating film into consideration.

Such a terminal hydroxyl group-blocked polydiorganosiloxane has aviscosity of 50 to 10,000,000 mPa·s at 25° C., and preferably 1,000 to2,000,000 mPa·s. If the viscosity is less than 50 mPa·s, the curedcoating film becomes brittle, and if the viscosity exceeds 10,000,000mPa·s, it is difficult to obtain a stable emulsion.

When the polydiorganosiloxane as the component (A) has a viscosityfalling in the above-described range at 25° C., one element may be usedalone or two elements or more may be used as a mixture. Besides, it isdesirably linear polysiloxane but may have partly a branch structure ora network structure. And, if the polydiorganosiloxane of the component(A) has a viscosity of 100,000 mPa·s or more, it is desirable to produceby a known emulsion polymerization to obtain a stable emulsion.

The polyorganohydrogensiloxane of the component (B) has at least threehydrogen atoms which are bonded to the silicon atoms and undergoes adehydrogenation condensation reaction with the terminal hydroxylgroup-blocked polydiorganosiloxane of the component (A) to form anetwork structure.

In this polyorganohydrogensiloxane of (B), the organic group bonded tothe silicon atoms in the molecule is the same one to the organic groupbonded to the silicon atoms of the component (A). The siloxane chain ofthe polyorganohydrogensiloxane may be any of linear, branched andcyclic.

The blending amount of the component (B) is desirably 0.5 to 20 parts byweight to 100 parts by weight of the polydiorganosiloxane of thecomponent (A). When the blending amount of the component (B) is lessthan 0.5 part by weight, the curing speed is too slow to form thecoating film continuously, and when it exceeds 20 parts by weight, it isnot desirable because the cured coating film becomes brittle.

The curing catalyst of the component (C) used in the present inventionis a catalyst for promoting a dehydrogenation condensation reactionbetween the hydroxyl group of the terminal hydroxyl group-blockedpolydiorganosiloxane of the component (A) and an Si—H bond of thepolyorganohydrogensiloxane of the component (B). The curing catalystsmay be metallic fatty acid salts, amines, quaternary ammonium hydroxidesor the like. They can be used together.

Examples of the metallic fatty acid salts include dibutyltin diacetate,dibutyltin dioctoate, dibutyltin dilaurate, dibutyltin dioleate,dibutyltin distearate, tributyltin acetate, tributyltin octoate,tributyltin laurate, dioctyltin diacetate, dioctyltin dilaurate,diethyltin dioleate and monomethyltin dioleate which have hydrocarbongroups directly bonded to metallic atoms, and zinc octenate, ironoctenate and tin octenate which do not have hydrocarbon groups directlybonded to metallic atoms.

Examples of the amines include organic amines such as monomethylamine,dimethylamine, monoethylamine, diethylamine, ethylenediamine andhexamethylenetetramine; silane compounds having an amino group such asα-aminopropyltriethoxysilane and their salts. Examples of the quaternaryammonium hydroxides include tetramethylammonium hydroxide,dimethylbenzyl ammonium hydroxide and their salts.

A blending amount of the curing catalyst of (C) is preferably in a rangeof 0.1 to 10 parts by weight to 100 parts by weight of thepolydiorganosiloxane of (A) above. when the blending amount of thecuring catalyst of (C) is less than 0.1 part by weight, the curing speedis too slow to form the continuous coating film, and when it exceeds 10parts by weight, it is not desirable because the composition stabilityis degraded.

To produce the emulsion containing the above-described components (A),(B) and (C), the individual components may be solely formed intoemulsions by using an appropriate emulsifying agent and then mixed, ortwo or three of the components may be mixed and formed into an emulsion.An emulsion produced by an existing mechanical emulsification oremulsion polymerization can be used appropriately.

The component (D) is one of the characteristic components of the presentinvention and provides the coating film obtained from the coating agentcomposition of the present invention with adhesiveness and abrasionresistance which are good for a rubber substrate and the like. And, itprovides stability to the emulsion after mixing the individualcomponents, making it possible to provide a long usable life.

The component (D) contains at least one of the chlorinated polyolefineand the acryl-modified polyolefine. And, it is preferable that thechlorinated polyolefine and the acryl-modified polyolefine are blendedin a state of emulsion.

In the chlorinated polyolefine emulsion, a chlorine content or a basepolyolefine molecular weight is not particularly limited, but it isdesirable to use modified chlorinated polypropylene having a maleicanhydride group as a reaction group, namely an emulsion of maleicanhydride-modified chlorinated polypropylene because of the easiness ofavailability. It is particularly desirable to use an emulsion of themaleic anhydride-modified chlorinated polyolefine having a molecularweight of 10,000 to 200,000, a chlorine content of 5 to 35 wt % and amaleic anhydride group content of 0.1 to 30 wt %.

In the acryl-modified polyolefine emulsion, an acrylic modification rate(content) and a base polyolefine molecular weight are not particularlyrestricted, but it is desirable to use acryl-modified polyolefine havinga maleic anhydride group, as a reaction group, namely an emulsion ofmaleic anhydride•acryl-modified polyolefine because of the easiness ofavailability. Especially, it is desirable to use the emulsion of themaleic anhydride•acryl-modified polyolefine having a molecular weight of10,000 to 200,000, an acryl group content of 5 to 35 wt % and a maleicanhydride group content of 0.1 to 30 wt %.

The component (D) content as a total of the chlorinated polyolefine andthe acryl-modified polyolefine is determined to be 5 to 150 parts byweight, and more preferably 50 to 100 parts by weight, to 100 parts byweight of the polydiorganosiloxane (A). The total content of thecomponents (D) is limited to the above-described range because, when itis less than 5 parts by weight, the purpose of blending to improve theadhesiveness with the rubber substrate and the abrasion resistancecannot be achieved satisfactorily. Meanwhile, when the content exceeds150 parts by weight, the effect of improvement of the adhesiveness withthe rubber substrate and the abrasion resistance is saturated, andweatherability and other properties are degraded.

The fine spherical particles comprised of the rubber-like elastomer ofthe component (E) are also one of the characteristic components. Thefine spherical particles of the rubber-like elastomer lower acoefficient of friction of the coating film obtained from the coatingagent composition of the present invention, provide good lubricatingproperties, and also provide outstanding abrasion resistance. And, theproduction of creaking sound can be prevented when a coated mold part isrubbed against the surface of wet glass. Besides, a demand for no damageto a coated metal surface by friction can be satisfied.

The rubber-like elastomer forming the fine spherical particles is notlimited to a particular type, but an elastic material having a value ofhardness (rubber hardness) of less than 90, more preferably in a rangeof 60 to 80, measured according to JIS K 6253 is used. When fineparticles of a hard or semihard material having hardness of 90 or moreare used, the effects for prevention of creaking sound in theabove-described water leaked state and prevention of damage to a coatedmetal surface cannot be obtained satisfactorily.

As the fine spherical particles of the rubber-like elastomer of thecomponent (E), cross-linked urethane-based, cross-linked polymethylmethacrylate-based, cross-linked polyacrylic ester-based, cross-linkedpolybutyl methacrylate-based and silicone-based polymers are desirablyused in view of the ease of availability and synthesis. And, such finespherical particles have desirably an average particle diameter of 0.1to 100 μm, and more preferably 1 to 20 μm. When the average particlediameter is less than 0.1 μm, the coating film has inferior lubricatingproperties, and when the average particle diameter exceeds 100 μm, theabrasion resistance becomes poor.

The blending amount of the fine spherical particles of the rubber-likeelastomer (E) is 10 to 150 parts by weight, and more preferably 30 to 75parts by weight, to 100 parts by weight of the polydiorganosiloxane (A).The blending amount of the component (E) was limited to the above rangebecause the coating film has poor lubricating properties when theblending amount is less than 10 parts by weight, and because the coatingproperty is degraded, the particles are aggregated and the coating filmhas a rough feeling when it exceeds 150 parts by weight.

To improve wettability in the surface of the substrate of rubber or thelike and to prevent a deviation to one side or repellency at the time ofcoating, alkylamine oxide can be added in a range of 0.5 to 10 wt % at asolid content ratio to the emulsion. The alkylamine oxide can bedimethyl alkylamine oxide. Examples of the alkyl group include a laurylgroup, a myristyl group, a natural oil and fat denatured group ofcoconut oil or the like.

For further improvement of the adhesiveness, an emulsion containingwater-insoluble amino group-containing polyorganosiloxane can be addedto the coating agent composition of the embodiment. The adding amount ofthe water-insoluble amino group-containing polyorganosiloxane isdetermined to be 3 to 50 wt % of the solid content of the emulsioncomposition in view of the coating efficiency and coating property, andit is desired to adjust the water-insoluble amino group-containingpolyorganosiloxane with water so to have a component concentrationfalling in the above range.

The water-insoluble amino group-containing polysiloxane ispolyorganosiloxane represented by the general formula: [R_(a)¹Si(OR²)_(b)O_((4−a−b)/2)]_(n)

(where, R¹ indicates at least two selected from a hydrogen atom and amonovalent substituted or unsubstituted hydrocarbon group, at least twoamong all R¹ in one molecule are monovalent hydrocarbon groupssubstituted by substituted or unsubstituted amino groups bonded to asilicon atom via at least one carbon atom; R² indicates at least oneselected from a hydrogen atom and a monovalent substituted orunsubstituted hydrocarbon group; a and b indicate numerals satisfyingthe relationships 1≦a≦2.5, 1≦a+b≦2.5, 0≦b≦0.5, and n indicates numeral 4to 5,000).

In this amino group-containing polysiloxane, examples of the substitutedor unsubstituted amino groups bonded to the silicon atom via at leastone carbon atom include an aminomethyl group, β-aminoethyl group,γ-aminopropyl group, δ-aminobutyl group, γ-(methylamino)propyl group,γ-(ethylamino)propyl group, N-(β-aminoethyl)-γ-aminopropyl group andN-(β-dimethylaminoethyl)-γ-aminopropyl group. Examples of R¹ other thanthese amino group-containing hydrocarbon groups include a hydrogen atom,alkyl groups such as methyl group, ethyl group, propyl group, butylgroup and hexyl group; alkenyl groups such as a vinyl group and propenylgroup; aryl groups such as a phenyl group; aralkyl groups such as aphenethyl group; and those having hydrogen atoms of these hydrocarbongroups partly substituted by halogen atoms or nitril groups. Thehydrogen atom, methyl group, vinyl group and phenyl group are desirable,and the methyl group is particularly desirable because of the ease ofsynthesis and handling.

Examples of R² include a hydrogen atom, methyl group, ethyl group,propyl group and butyl group and so on. In them, the hydrogen atom,methyl group and ethyl group are desirable because of the ease ofsynthesis and handling.

In the general formula (average compositional formula) representing thewater-insoluble amino group containing polysiloxane, a and b arenumerals satisfying the above-described relationships, and when a and(a+b) are less than 1 or exceed 2.5, adhesiveness to the substrate isnot improved. And, b indicates the number of the hydroxyl group oralkoxy group bonded to the silicon atoms and is desired to be 0.5 orless. When it exceeds 0.5, the storage stability of the coating agent isdegraded.

Besides, the water-insoluble amino group-containing polysiloxane has apolymerization degree n falling in a range of 4 to 5,000, and preferably4 to 1,000, from the viewpoint of the ease of synthesis, the viscosityof the composition before curing falling in a range not hindering thework and the adhesiveness of the cured coating film. When thepolymerization degree n is smaller than 4, the adhesiveness is notimproved satisfactorily, and when the polymerization degree n is biggerthan 5,000, it is difficult to synthesize the polysiloxane and theviscosity increases, making it difficult to handle.

The amount of the amino group in this water-insoluble aminogroup-containing polysiloxane is desirably an amount solely capable ofproviding a water insoluble state, and an amount of 100 to 15,000(g/mol), preferably 150 to 1,000 (g/mol), in amino equivalent is usable.The water-insoluble amino group-containing polysiloxane having the aminoequivalent exceeding 15,000 (g/mol) or less than 100 (g/mol), cannotimprove the adhesiveness.

The coating agent composition of the embodiment of the present inventionis coated onto the surface of the substrate made of paper, rubber,plastic or metal by a method such as dip coating, spray coating, brushcoating, knife coating or roll coating. Then, the coated substrate isleft standing at room temperature for several hours or heatedappropriately depending on the heat resistance of the substrate to curethe coated film. The heating conditions are preferably set to atemperature of 120 to 180° C. for 10 to 30 seconds for the papersubstrate, a temperature of 80 to 180° C. for 1 to 5 minutes for therubber substrate, and a temperature of 70 to 150° C. for 30 seconds to 2minutes for the plastic substrate.

In order to improve the adhesiveness of the coating film with thesubstrate, various types of silane coupling agents may be added alone oras a mixture with or without partial condensation to the coating agentcomposition of the embodiment.

Besides, according to the embodiment, an inorganic or organicultraviolet absorber for improvement of weatherability,polydimethylsiloxane having a high viscosity for further improvement oflubricating properties, an organic or inorganic filler having an averageparticle diameter of 0.01 to 100 μm formed of polyalkyl silsesquioxane,polyolefine such as polyethylene, polycarbonate resin or the like forimprovement of a matte texture and lubricating properties, and aninorganic pigment for coloring can be added in a range not failing toachieve the object of the present invention. If necessary, a thickener,an antifoaming agent and a preservative can be mixed appropriately.

When the coating agent composition of the embodiment of the invention isused to treat the surface of each type of substrate, a cured coatingfilm excelling in uniform applying property and the adhesiveness andabrasion resistance to the substrate in comparison with a treatment by aconventional silicone composition can be obtained. And, a coating filmhaving outstanding adhesiveness and abrasion resistance can be formed ona rubber or plastic substrate, particularly a substrate formed of foamedor non foamed EPDM rubber, on which a coating film having sufficientadhesiveness could not be formed by using the conventional siliconecomposition for forming a non adhesive coating film.

And, according to the coating agent composition, the cured coating filmis formed at room temperature or a relatively low temperature.Therefore, the cured coating film, which can be formed on a substratehaving a low heat resistance and a substrate which is large and hardlyheat-treated, and has good non tackness to other substances, waterrepellency and outstanding abrasion resistance, is formed. Besides, theemulsion of each component has outstanding storage stability, stabilityafter mixing the emulsions of individual components is outstanding, anda usable life is long.

Accordingly, the coating agent composition of the present invention canbe used suitably as a surface treatment agent for rubber parts such asautomobile weather-strips, printer blades, rubber vibration-isolators,building material gaskets formed of EPDM rubber and so on. Besides, thecoating agent composition of the present invention is used to providevarious types of substrates of rubber, plastic and the like with nontackness and water repellency.

EXAMPLES

Examples of the present invention will be described specifically, but itis to be understood that the invention is not limited to the examples.In the examples, all physical properties such as a viscosity indicatedare values determined at 25° C. and a relative humidity of 50%, and theparts in Table 1 indicate parts by weight.

Examples 1 to 5, Comparative Examples 1 to 6

Individual components shown in Table 1 were mixed in the proportionsindicated vertically in the table to prepare coating agent compositions.

In Table 1, the polydimethylsiloxane emulsion is an emulsion-polymerizedemulsion containing terminal hydroxyl group-blocked polydimethylsiloxanehaving a viscosity of 1,400,000 mPa·s at a ratio of 50 wt %, and themethylhydrogen siloxane emulsion is a mechanical emulsified emulsioncontaining polymethylhydrogen siloxane represented by the averageformula: (CH₂)₃SiO(CH₃HSiO)₅₀Si(CH₃)₃ at a ratio of 30 wt %.

Chlorinated polyolefine emulsion-1 is an emulsion containing maleicanhydride-modified chlorinated polypropylene having a molecular weightof about 60,000, a maleic anhydride content of 1.6 wt %, a chlorinecontent of 17 wt %, at a ratio of 30 wt % and chlorinated polyolefineemulsion-2 is an emulsion containing maleic anhydride-modifiedchlorinated polypropylene having a molecular weight of about 100,000, amaleic anhydride content of 1.5 wt %, a chlorine content of 15 wt %, ata ratio of 30 wt %.

The acryl-modified polyolefine emulsion is an emulsion containing maleicanhydride•acryl-modified polyolefine having a molecular weight of about68,000, a maleic anhydride content of 1.6 wt %, an acryl content of 3 wt% (an ethylene-propylene copolymer of propylene 97.5 mol % and ethylene2.5 mol %) at a ratio of 30 wt %.

The water-insoluble amino group-containing polysiloxane is anemulsion-polymerized emulsion containing amino group-containingpolysiloxane which is represented by the average formula:{H₂N(CH₂)₂NH(CH₂)₃}SiO[{(CH₃)₂SiO}₁₅OH]₃ at a ratio of 30 wt %, andwater-soluble amino silicone is represented by the average formula:(CH₃)₃SiO[{H₂N(CH₂)₂NH(CH₂)₃}CH₃SiO]₁₀₀(CH₃)₃.

Elastic fine spherical particles-1 is powder (an average particlediameter of 5 μm) of a dimethyl silicone cross-linked elastomer havinghardness (hereinafter simply referred to as JIS hardness) of 75 measuredby a durometer type A according to JIS K6253, elastic fine sphericalparticles-2 is cross-linked urethane soft powder (an average particlediameter of 6 μm) having JIS hardness of 74, and elastic fine sphericalparticles-3 is cross-linked polyacrylic ester powder (an averageparticle diameter of 15 μm) having JIS hardness of 78.

Non elastic fine spherical particles are powder of hard resin having theJIS hardness of 90 or more, non elastic fine spherical particles-1 ispolymethyl silsesquioxane powder (an average particle diameter of 6 μm),non elastic fine spherical particles-2 is cross-linked urethane hardpowder (an average particle diameter of 10 μm), and non elastic finespherical particles-3 is nylon powder (an average particle diameter of 5μm).

Then, the prepared coating agent composition was coated on the surfaceof an foamed EPDM rubber sheet by a spray gun. Then, water wasvolatilized from the coated film, which was then heated to dry by anoven at 150° C. for 10 minutes to obtain a cured coating film having athickness of 10 μm.

The foamed EPDM rubber sheet having the surface treated as describedabove was examined for adhesiveness, solvent resistance, a coefficientof friction, abrasion resistance and creaking sound of the cured coatingfilm. And, the usable lives of the coating agent compositions wereexamined. The results are shown in Table 1.

The adhesiveness, solvent resistance, coefficient of friction, abrasionresistance, creaking sound and usable lives of the coating films wereexamined by the following methods.

[Adhesiveness]

Eleven parallel lines were marked in a matrix at intervals of 1 mm onthe surface of the coating film to cross-cut 100 grids, an adhesive tapewas adhered to them and peeled afterward, and the grids not peeled werecounted. The adhesive tape was prepared by coating a siliconepressure-sensitive adhesive YR3340 (produced by GE Toshiba Silicones) inthickness of 40 μm on a polyester tape and leaving the tape standing ina constant temperature and humidity chamber for 48 hours.

[Solvent Resistance]

The surface of the coating film was rubbed reciprocally 30 times withwiping paper impregnated with hexane, and the rubbed surface of thecoating film was examined.

[Coefficient of Friction]

A glass plate of 10 mm wide and 100 mm long was placed on the surface ofthe coating film, and a load of 200 g was applied to move the glassplate at a speed of 900 mm/min. And, a dynamic friction coefficient wasdetermined from the obtained tensile stress. A maximum static frictioncoefficient is a value at the time when the glass plate is started tomove.

[Abrasion Resistance]

The glass piece shown in FIG. 1 with a contact surface formed to have acurved surface of 2 mm in thickness and 20 mm in width was used as arubbing part. The rubbing part was pressed against the surface of thecoating film under a load of 400 g and moved to reciprocate for adistance of 15 cm at a speed of 60 times/min. to conduct the abrasiontest. The abrasion resistance was evaluated according to the number ofreciprocated times when the surface of the foamed EPDM rubber sheet wasworn out by abrasion.

[Creaking Sound]

Water of 0.5 mL was uniformly spread on a glass plate of 100 mm in widthand 100 mm in length, and sound produced when the surface of the coatingfilm was rubbed against the glass plate was examined. It was judged goodwhen no sound was produced.

[Usable Life]

The coating agent compositions were prepared, and a time until a gel wasproduced in each solution at room temperature (25° C.) was examined.TABLE 1 Examples Comparative Examples 1 2 3 4 5 1 2 3 4 5 6 COMPOSITIONPolydimethylsiloxane 20 20 20 20 20 20 20 20 20 20 20 PARTS EmulsionMethylhydrogen siloxane 2 2 2 2 2 2 2 2 2 2 2 Emulsion Chlorinatedpolyolefine 20 20 20 20 20 20 emulsion-1 Chlorinated polyolefine 20emulsion-2 Acryl-modified polyolefine 20 20 Emulsion Dibutyltindilaurate 1 1 1 1 1 1 1 1 1 1 1 Aqueous solution of 30% 2 2 2 2 2 2 2 22 2 2 dimethyl laurylamineoxide Water-insoluble amino 10 10 10 10 10 1010 10 10 10 10 group-containing polysiloxane Elastic fine spherical 5 55 particles-1 Elastic fine spherical 5 5 particles-2 Elastic finespherical 5 particles-3 Water-soluble amino 1.5 1.5 Siliconeγ-Aminopropyltriethoxysilane 1.5 1.5 Acetic acid 1.5 1.5Glycidoxypropyltri- 1.5 1.5 methoxysilane Non elastic fine spherical 5 55 particles-1 Non elastic fine spherical 5 particles-2 Non elastic finespherical 5 Particles-3 Water 40 40 40 40 40 54 54 40 40 40 40 *1Adhesiveness  100/  100/  100/  100/  100/  100/  100/  100/  100/  100/ 100/ 100 100 100 100 100 100 100 100 100 100 100 Solvent resistanceGood Good Good Good Good Good Good Good Good Good Good Coefficient offriction 0.30 0.31 0.25 0.18 0.33 0.27 0.15 0.15 0.08 0.10 0.19 Abrasionresistance 15000 14000 6000 7000 10000 3000 2000 3000 7000 3000 3000(Rubbing times) Creaking sound Good Good Good Good Good Good *2 *2 *2 *2*2 Usable life 72 h or 72 h or 72 h or 72 h or 72 h or 8 h 8 h 72 h or72 h or 72 h or 72 h or (Hours) more more more more more more more moremore*1: physical properties*2: Production of Creak

As described above, according to the coating agent composition of thepresent invention, the cured coating film having quite excellentadhesiveness, good lubricating properties, non tackness and waterrepellency to the substrate formed of rubber or plastic, andparticularly the substrate made of the foamed or non foamed EPDM rubber,can be formed. This coating film has a low coefficient of friction andgood abrasion resistance.

Therefore, the coating agent composition of the present invention issuitably used as a surface treatment agent for rubber parts such asautomobile weather-strips, printer blades, rubber vibration-isolatorsand building material gaskets.

1. A coating agent composition, including: an emulsion containing: (A)polydiorganosiloxane having a viscosity of 50 to 10,000,000 mPa·s at 25°C. and having both terminal ends blocked by hydroxyl groups, (B)polyorganohydrogensiloxane having at least three hydrogen atoms bondedto silicon atoms in one molecule, (C) a curing catalyst, and (D)chlorinated polyolefine and/or acryl-modified polyolefine, (E) finespherical particles comprised of a rubber-like elastomer having hardnessof less than 90, wherein the fine spherical particles (E) are mixed todisperse into the emulsion.
 2. The coating agent composition accordingto claim 1, wherein the fine spherical particles of the component (E)are fine spherical particles comprised of a rubber-like elastomer havinghardness of 60 to
 80. 3. The coating agent composition according toclaim 1, wherein the total content of the chlorinated polyolefine andthe acryl-modified polyolefine of the components (D) is 5 to 150 partsby weight to 100 parts by weight of the polydiorganosiloxane of thecomponent (A).
 4. The coating agent composition according to claim 1,wherein the content of the fine spherical particles of the rubber-likeelastomer (E) is 10 to 150 parts by weight to 100 parts by weight of thepolydiorganosiloxane (A).
 5. The coating agent composition according toclaim 1, further comprising alkylamine oxide and/or water-insolubleamino group-containing polyorganosiloxane.
 6. The coating agentcomposition according to claim 1, wherein the coating agent compositionis coated on a mold part formed of an foamed or non foamedethylene-propylene-diene ternary copolymer.
 7. The coating agentcomposition according to claim 2, wherein the total content of thechlorinated polyolefine and the acryl-modified polyolefine of thecomponents (D) is 5 to 150 parts by weight to 100 parts by weight of thepolydiorganosiloxane of the component (A).
 8. The coating agentcomposition according to claim 2, wherein the content of the finespherical particles of the rubber-like elastomer (E) is 10 to 150 partsby weight to 100 parts by weight of the polydiorganosiloxane (A).
 9. Thecoating agent composition according to claim 2, further comprisingalkylamine oxide and/or water-insoluble amino group-containingpolyorganosiloxane.
 10. The coating agent composition according to claim2, wherein the coating agent composition is coated on a mold part formedof an foamed or non foamed ethylene-propylene-diene ternary copolymer.